PROJECT SUMMARY The objective of this project is to improve scientific understanding of the etiology of harsh discipline in terms of the role individual parent and dyadic parent-child regulatory processes play in harsh discipline use. Harsh discipline, defined as the parent?s use of coercive and verbally aggressive commands and physical punishment (e.g., grabbing, shaking, spanking) to discipline children, is widely condemned by researchers and practitioners for its detrimental effects on children and yet still widely practiced by parents. This suggests that either scientists lack information about what mechanisms underlie the recurrent use of harsh discipline and/or that programs to prevent harsh discipline are insufficient. To more successfully reduce harsh discipline through intervention, we need to identify intervention targets that are mechanistic in maintaining harsh discipline use over time and are malleable in intervention. A prime candidate is regulatory processes in the parent and parent-child dyad, which have been shown to underlie harsh discipline use and act as markers of improvement in family intervention. Harsh parents show maladaptive emotional and biological reactivity and lower executive function than controls, and parent-child dyads characterized by harsh discipline show more affective rigidity, poorer behavioral contingencies (e.g., coercion), and weaker biological synchrony. Parent self-regulation and parent-child coregulation involve interrelated affective, behavioral, cognitive, and biological processes that unfold in real time. For their ecologically valid assessment, measures of dynamic, time-sensitive regulatory responses in context are needed. But due to the complexity of modeling regulatory processes and the system-level dynamics of interdependent dyads, most studies assess individuals, static indicators, and single dimensions of regulatory processes. The present proposal will conduct an integrated assessment of multiple regulatory domains to answer the question of how individual and dyadic regulatory processes interact to support harsh discipline use over time. The dynamic analytic approaches proposed to model regulatory processes have been shown to explain variance in risk above and beyond static indicators of regulatory skills. Mixture structural equation models of emotional, behavioral, cognitive, and biological regulatory processes at the individual and dyadic levels will be used to test relations among major constructs. Programs previously shown to reduce HD often target the parent or the child but not dyadic processes. Very few directly address parent self-regulation, and when they do, may only address one domain (e.g., emotion regulation). Cumulative contextual risk for HD (e.g., history of trauma, poverty, low parenting resources) is intergenerationally stable and thus difficult to change. Thus, to illustrate the measurable potential of parent and parent-child regulatory processes as malleable intervention targets, the proposed research will also examine whether they explain variance in HD above and beyond cumulative contextual risk for HD.